Shy-you can post your weight whenever you want. We've never had (that I can recall) specific weigh-in days. In general, though-you should weigh yourself at the same time each week (ie Monday mornings after going to the bathroom). Or weigh more often 2-3X/week-again always at the same time of day.

I think the 3X/week you're referring to is for the Turkey Day challenge-and even then, people can weigh whichever days they want to, it was just suggested that it be 3X weekly until Thanksgiving (US)